Expansible bit screw driver



June 12, 1951 c. o. M LEAN EXPANSIBLE BIT SCREW DRIVER Filed Dec. 19, 1947 Char/es 0. Mai ean IN V EN TOR.

Patented June 12 I 1951 UNITED STATES PATENT OFFICE 2,556,395 EXPANSIBLE BIT SCREW DRIVER Charles 0. MacLean, East Greenwich, R. I.

Application December 19, 1947, Serial No. 792,692

3 Claims. (Cl. 145-50) This invention relates to new and useful improvements in screw-drivers and the primary object of the present invention is to provide a screwdriver including a pair of spreadable companion jaws insertable in the kerf of a fastener, and embodying novel and improved means for selectively spreading said jaws to frictionally engage or wedge in the kerf of a fastener.

Another important object of the present invention is to provide a screw-driver so designed as to facilitate the same to frictionally support fasteners in such a manner as to facilitate fasteners to be installed in machinery, electrical apparatus, and the like, where a users hand would usually be restricted and difiicult to extend.

A further object of the present invention is to provide an expansible jaw screw-driver including means for spreading the jaws of said screw driver and novel and improved means for actuating said jaw spreading means in a selected locked position.

A still further aim of the present invention is to provide an expansible jaw screw-driver that is simple and practical in construction, strong and reliable in use, small and compact in structure, neat and attractive in appearance, relatively inexpensive to manufacture, and otherwise well adapted for the purposes for which the same is intended.

Other objects and advantages reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming part hereof, wherein like numerals refer to like parts throughout, and in which:

Figure 1 is a side elevational view of the present expansible jaw screw-driver;

Figure 2 is an enlarged longitudinal vertical sectional view taken substantially through the center of Figure 1, and with parts thereof broken away and shown in section;

Figure 3 is a transverse horizontal sectional view taken substantially on the plane of section line 33 of Figure 2;

Figure 4 is a perspective view of the jaw actuating member used in conjunction with the present invention;

Figure 5 is a group perspective view of the gripping jaws used in conjunction with the present invention, and showing the same disassembled; and

Figure 6 is a fragmentary side elevational view of the lower end of the present tool, showing the same in use, and with parts broken away and shown in section.

Referring now to the drawings in detail, wherefin a finger receiving plate 36.

tionally positioned in the slot 32 and bore 34 rein for the purpose of illustration, there is disclosed a preferred embodiment of the present invention, the numeral I0 represents a tubular body or shank having an open lower end l2 and a preferably open upper end M. The upper end [4 is suitably fixed in an annular recess I6 provided in the lower end of a suitable handle I8 having a longitudinal bore 20 in which there is rotatably and slidably'mounted the outer end 22 of an adjustable rod or shaft 24. This shaft 24 is provided with an enlarged externally threaded central portion 25 that receivably engages internal threads 28 projecting fromthe inner peripheryof the body Ill. The outer' extremity 30 of the shaft 24 is provided with a transverse opening or slot 32 that aligns'a diametrical bore 34 provided A pin 38 frictains the plate positioned relative to the shaft 24.

Rigidly secured to the lower or inner extremity 40 of the shaft 24, is the upper closed end 42 of a sleeve-like piston 44 that is workable within the shank Ill.

The numerals 46 and 48 represent a pair of companion jaws generally, having opposed hearing faces 50 and 52 that normally frictionally engage each other. One of the jaws, for example jaw 48, is provided with a pair of outwardly projecting, spaced pivot-ears 54 that extend outwardly from the face 52 of said jaw to loosely engage recesses 56 provided in the other of said jaws, namely, jaw 46.

Pivotally securing the ears 54 in the recesses 56, is a pivot pin 58, the ends 60 and 62 of which pivotally engage apertures 64 and 66 provided in the shank l0, adjacent its lower end l2. It should be noted, that one of these apertures, for example aperture 64, terminates in an arcuate slot 66a that communicates with a longitudinal slot 68 provided in the end I2 of the shank, whereby the pin and jaws'may be disengaged from the shank for replacement by similar jaws of a larger or smaller size. The inner ends of the jaws 46 and 48 terminate in elongated cams H! and 12 having inclined and arcuate outer peripheries 14. A coil spring 15 positioned between the said cams normally retains the bearing faces of the laws 46 and 48 in a frictionally clamped position, as shown best in Figure 2 of the drawings.

Frictionally positioned in the lower end l2 of the shank Ill, and frictionally bearing upon the pivot pin 58, is a support ring 16 that engages the lower end of a coil spring 18. .flhis spring 18 urges a slidable cam actuating ring normally against an annular shoulder 82 provided in the inner periphery of the shank adjacent end l2.

The outer ends of the jaws 46 and 48 terminate in substantially flat extensions 84 and 86 having knurled or roughened outer faces 88.

In practical use of the device, by rotating the shaft 24 in one direction, the same will move longitudinally in the shank [0, so that the member 44 will fric'tionally :engage the ring 80 and force the same against the inclined, rounded surfaces of the cams, thus pivoting the outer ends of the jaws 46 and 48 outwardly, so that the knurled surface of the tips 84 and :86 will "frictionally engage the kerf 90 provided in one end of a suitable fastener 92. In suchapos'it-ion, the handle l8 may be manipulated ina -,convenient manner so that the fastener may be inserted in openings otherwise difficult for an operators hand to extend.

In'view 'of the foregoing.description taken in conjunction with the accompanying drawings, it isbelieved that a clear understanding of-the device will be quite apparent to'those skilled in this *art. A more detailed description is accordingly deemed unnecessary.

It is to be "understood, :however, -that even though there is herein shown and described a :preferred embodiment of the invention the same 'is susceptible to certain changes fully comprehended by the spirit of the invention as herein described-and the scope of the appended claims. Having "described the invention, what is claimed as new is:

va hollow shank open -:at;its lower end, a handle fixed to the opposite :end of said shank, a pair of companion jaws pivoted to the lower end of said shank, thegouterzends-ofsaid jaws projecting outwardly :from the lower ,end of said shank, cams carried by the inner ends of said j aws and positioned withintheishank, a cam-engaging ring slidably mounted within said shank and {embracingithe inner'ends-of'said jaws for-actuating said jaws to a spread .iposition, means for normally retaining said jaws in :a clamped position, means .=for selectively :adjustingsaid cam actuating member within said shank, a'support ring mounted in the FIOWEI' ;end -of said shank, and a spring member biased between said support ring and jaws, cams carried by the inner end portions of said jaws, a jaw actuating ring member embracing said oams, :a coil spring embracing the inner end portions of said jaws and biased between "said support ring and said jaw actuating ring member, a resilient member biased between the inner end portions of said jaws and urging the outer end portions of said jaws toward each other, and an adjustable member carried by said .shank for forcing-the jaw "actuating ring member against the cams to urge the inner-end portions .ofsaid jaws toward each other and to urge the outer end portions of said jaws apart.

3. The combination of claim .2 wherein said means pivotally securing the jaws together intermediate their ends and "also securing the jaws to the lower end of the shank includes a pin extending through the jaws, said-shank having an aperture adjacent its lower end receiving one endcf said pin, and a key slot provided in the shank adjacent the lower end thereof and diametrically opposite from the aperture receiving the other end of said pin, said pin being removable from said aperture-and-said slot for removing the jaws from the lower end of said shank.

CHARLES O. MAoLEAN.

REFERENCES CITED The 'following references are :of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,164,704 Courembis Dec. 21, 1915 FOREIGN PATENTS Number Country Date 74,147 Switzerland Jan. 16, 1917 441,233 Germany Feb. 23, 1927 

